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Why is the shovel operator (
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Proof:
a = 'foo'
a.object_id #=> 2154889340
a << 'bar'
a.object_id #=> 2154889340
a += 'quux'
a.object_id #=> 2154742560
So << alters the original string rather than creating a new one. The reason for this is that in ruby a += b is syntactic short...
On localhost, how do I pick a free port number?
...do I figure out which port is available? I assume I cannot listen on port 80 or 21?
5 Answers
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How to use hex color values
...f, green ff and blue ff. You can write hexadecimal notation in Swift using 0x prefix, e.g 0xFF
To simplify the conversion, let's create an initializer that takes integer (0 - 255) values:
extension UIColor {
convenience init(red: Int, green: Int, blue: Int) {
assert(red >= 0 &&amp...
Best way to test if a row exists in a MySQL table
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edited Sep 4 '19 at 19:20
SovietFrontier
1,5441010 silver badges2727 bronze badges
answered Nov 4 '09 ...
Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
...le(a = c(1, 2), b = c(11, 12))
newDT <- DT
.Internal(inspect(DT))
# @0000000003B7E2A0 19 VECSXP g0c7 [OBJ,NAM(2),ATT] (len=2, tl=100)
# @00000000040C2288 14 REALSXP g0c2 [NAM(2)] (len=2, tl=0) 1,2
# @00000000040C2250 14 REALSXP g0c2 [NAM(2)] (len=2, tl=0) 11,12
# ATTRIB: # ..snip..
.Inte...
Formatting a number with exactly two decimals in JavaScript
...ich rounds my numbers to two decimal places. But I get numbers like this: 10.8, 2.4, etc. These are not my idea of two decimal places so how I can improve the following?
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List comprehension on a nested list?
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answered Aug 6 '13 at 6:05
Andrew ClarkAndrew Clark
171k2525 gold badges236236 silver badges278278 bronze badges
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Replacing NAs with latest non-NA value
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divibisan
7,90699 gold badges2626 silver badges4343 bronze badges
answered Oct 12 '11 at 5:32
Dirk EddelbuettelDir...
How can I update the current line in a C# Windows Console App?
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805
If you print only "\r" to the console the cursor goes back to the beginning of the current line...
Fastest way to check if string contains only digits
...tsOnly(string str)
{
foreach (char c in str)
{
if (c < '0' || c > '9')
return false;
}
return true;
}
Will probably be the fastest way to do it.
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